“The annual EBRI/ICI 401(k) database update report is based on large cross-sections of 401(k) plan participants. Whereas the cross-sections cover participants with a wide range of participation experience in 401(k) plans, meaningful analysis of the potential for 401(k) participants to accumulate retirement assets must examine how a consistent group of participants’ accounts change over time. Looking at consistent participants in the EBRI/ICI 401(k) database in the wake of the financial crisis (over the four-year period from year-end 2007 to year-end 2011):

• The average 401(k) account balance fell 34.8 percent in 2008, then rose from 2009 to 2011. Overall, the average account balance increased at a compound annual average growth rate of 5.4 percent over the 2007–2011 period, to $94,482 at year-end 2011.
• The median 401(k) account balance (half above, half below) increased at a compound annual average growth rate of 11.5 percent over the period, to $42,082 at year-end 2011.
• Analysis of a consistent group of 401(k) participants highlights the impact of consistent participation in 401(k) plans. At year-end 2011, the average account balance among consistent participants was 60 percent higher than the average account balance among all participants in the EBRI/ICI 401(k) database. The consistent group’s median balance was about two-and-a-half times the median balance across all participants at year-end 2011.”